I agree with Michael.
Break it into pieces, a couple hundred people at a time. Import it slowly and be careful not to duplicate profiles for people that already exist on Wikitree. With a tree that size, there’s bound to be some overlap with profiles already here.
I have a tree of 15000 people on my ancestry.com account, and I’m slowly bringing over the Wikitree. I’m doing it in small chunks, because that is the easiest way to avoid errors/headaches. Im sticking to profiles that are for people who are deceased and for people I have sources for. It’s going to take me along time, but I’d rather do it correctly first than incorrectly and try and fix things later.
I tried to import a large chunk at first, if about 1000 people, but it was an utter nightmare trying to avoid errors and duplicates. I have up and reluctantly changed my tactic to far smaller pieces. It was annoying at first, but now I’m glad I changed directions. The downside is that moving everything over is going to take a really really long time, the upside is that now I have far fewer issues to deal with. I’ve learned that slow and steady really is the best method with Wikitree.
In the long run, its probably made me a better amateur genealogist.
Best of luck with your tree!